1. Field of the Invention
This invention relates to a printing system that includes a plurality of printers, a densitometer and a printer control unit, and to a printer.
2. Description of the Related Art
Controlling a plurality of printers using a single printer control unit in order to output a number of prints in a short time is conceivable. In a case where the same image or the like is printed using a plurality of printers, often it is required that the images printed by each of the printers have a density that is constant. The density of a print that has been output from a printer is measured by a densitometer in order to check whether the density is constant or not. The printer is adjusted in such a manner that the measured density will take on a predetermined value.
When images or the like are printed by a plurality of printers, however, the user may not be able to tell from which printer an image was output. Hence there are occasions where adjustment of printer density cannot be performed using prints that have been output from a plurality of printers.
Accordingly, an object of the present invention is to adjust the density of each of a plurality of printers in a system comprising a plurality of printers.
According to a first aspect of the present invention, the foregoing object is attained by providing a system comprising a plurality of printers, a densitometer and a printer control unit.
Each printer of the plurality of printers has a printer head for printing at a density that is based upon print-density adjustment data applied thereto, and a first controller (first control means) for controlling the printer head so as to print density adjustment paper that includes unique identification information, which is different from that of other printers among the plurality of printers, and density measurement information.
The densitometer has a first reading unit (means) for reading the identification information on the density adjustment paper that has been output from the printer and outputting data representing the read identification information, and a second reading unit (means) for reading the density measurement information on the density adjustment paper that has been output from the printer and outputting data representing a read density measurement value.
Furthermore, the printer control unit has a generating unit (means) for generating print-density adjustment data based upon density measurement data that has been output from the second reading unit (means) of the densitometer, and a second controller (second control means) for applying the print-density adjustment data generated by the generating unit (means) to a printer, which is specified by identification information data that has been output from the first reading unit (means), from among the plurality of printers.
In accordance with the first aspect of the present invention, each printer of a plurality of printers outputs density adjustment paper that contains unique identification information (identification information represented by a unique color, characters or bar code, etc.), different from other printers of the plurality of printers, and density measurement information (a gray color, etc., having a prescribed density). When the density adjustment paper is output from a printer, the density measurement information and identification information on the density adjustment paper are read by the densitometer. Data representing the read density measurement information and data representing the identification information is output from the densitometer and applied to the printer control unit.
Density adjustment data is generated based upon the density measurement data output from the densitometer. The generated density adjustment data is applied to the printer specified by the data representing identification information output from the densitometer. A density adjustment is carried out in accordance with the density adjustment data in the printer to which the density adjustment data has been applied.
Even though the printing system includes a plurality of printers, the user is capable of performing density adjustment of a printer using the corresponding density adjustment paper without needing to be aware of which printer output the density adjustment paper, which is output from respective ones of the printers. Density adjustment of each printer of a plurality of printers can be executed comparatively accurately.
The first controller (first control means) of each printer of the plurality of printers controls the printer head so as to print density adjustment paper that includes, e.g., printer collateral information (output-timing information) in addition to the identification information and density measurement information.
In this case, the densitometer includes a third reading unit (means) for reading the printer collateral information of the density adjustment paper that has been output from the printer, and outputting data representing the read output-timing information. Further, the printer control unit includes an alert device (means) for issuing an alert when printer collateral information that has been output from the third reading unit of the densitometer is not printer collateral information that was obtained from density adjustment paper printed last.
By way of example, even if density adjustment paper has been output a plurality of times on different days, it can be determined from the collateral printer information that a sheet of density adjustment paper was one obtained when a density adjustment was being attempted. As a result, a density adjustment can be performed using density adjustment paper for which a density adjustment was being attempted.
The printers, printer control unit and densitometer constructing the above-described printing system may each be stand-alone devices.
For example, in the case of the printer, the printer would comprise a printer head for printing at a density that is based upon print-density adjustment data applied thereto, and a controller (control means) for controlling the printer head so as to print density adjustment paper that includes different unique identification information and density measurement information.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.